This research investigates visual object representation in children and adults with Williams syndrome, as well as normally developing children. People with Williams syndrome have particular difficulty reasoning about the spatial aspects of objects, such as the relations between objects, but seem relatively unimpaired with object category. We hypothesize that this pattern reflects deficits in the representation of the spatiotemporal characteristics of objects, specifically the ability to locate and track multiple objects through time and space, with comparative preservation in their representation of the object's category. Using well-established methodologies from adult psychology, we will examine working memory for an object's location and category, object tracking with and without occlusion, and enumeration of multiple objects. These studies will provide a more accurate characterization of the visuospatial deficits in WS, benefiting further research in three important ways. First, it will further our understanding of the functional divisions in object representation and the associated neurophysiological substrates, since researchers have begun to describe the brain abnormalities that accompany this disorder. Second, it will provide a foundation for addressing these impairments clinically. Third, it will increase our understanding of the effects of the gene deletion that is a marker of this syndrome.